body,html
  line-height: 1
  font-weight: 200
  font-family: "PingFang SC","STHeitiSC-Light","Helvetica-Light",Arial,sans-serif


border-1px($color)
  position: relative
  &:after
    display: block
    position absolute
    left: 0
    bottom: 0
    width: 100%
    border: 1px solid $color
    content: ' '

border-none()
  &:after
    display: none

bg-image($url)
  background-image: url($url + "@2x.png")
  @media (-webkit-min-device-pixel-ratio:3),(min-device-pixel-ratio:3)
    background-image: url($url + "@3x.png")